The overall goal of the proposed case-control study is to estimate the risk of specific childhood cancers associated with in utero exposure to pesticides (fungicides, herbicides and insecticides) used in agricultural settings, with particular emphasis on differential risk by race/ethnicity. In the process of addressing the study goal, we will be developing two tools which will have wider applications for public health research in Texas populations: 1) a geographic information system (GIS) capable of producing historical agricultural land use maps for a majority of Texas counties; and 2) a crop-specific Pesticide Exposure Index (PEI) for use in evaluating exposure to agricultural pesticides based on cropping and pesticide use patterns. These data applications will be of particular use in evaluating public health outcomes in rural populations.